For each definition, treatment effects of the medication compared with placebo were analyzed using the Cochran-Mantel-Haenszel test or Chi Square test.

A meta-analysis of the pooled results for the 4 medications established risk ratios to determine the definitions that best favored medication over placebo.

Results:

Two definitions performed best in the analyses.

Both definitions included 30% or greater reduction in pain and 10% or greater improvement in physical function.

They differed in that:

• One (FM30 short version) included 30% or greater improvement in sleep or fatigue,

• And the other (FM30 long version) required 30% or greater improvement in 2 of the following symptoms: sleep, fatigue, depression, anxiety, or cognition.

In the analysis of both versions, the response rate was 15% or greater for each medication and significantly greater than placebo.

The risk ratio favoring drug over placebo (95% CI) in the pooled analysis for the FM30 short version was 1.50 (1.24, 1.82), P 0.0001 or less; the FM30 long version was 1.60 (1.31, 1.96), P 0.00001 or less. [Note: a risk ratio of 1.0 would indicate no difference vs the placebo. RR’s of 1.50 and 1.60 would indicate a 50% greater response rate than placebo required with the FM30 short version and 60% greater response rate required with the FM30 long version, respectively.]
Conclusion:

Among the 24 responder definitions tested, 2 were identified as most sensitive in identifying response to treatment.